The rentier economy is not only dysfunctional but unjust. In this paper I use a moral economic approach to defend this proposition by going back to basic concepts. Drawing upon classical political economic theory and political theory, and the work of Hobson and Tawney and more recent theorists, I propose a set of complementary distinctions that deepen understanding of rentiership: earned and unearned income; wealth-creating and wealth-extracting investment; property and improperty. I then comment on the relations, similarities and differences between capitalists and rentiers. Next I review the changing relation between critiques of rentiership and notions of ‘free markets’ and ‘property-owning democracy’ in the history of capitalism, with particular emphasis on the relation of neoliberalism to rent-seeking. Finally, I briefly discuss the implications of rentiership for reducing inequality and averting global heating.